Boeing, which insisted just a few weeks ago that it would deliver the new 787 Dreamliner on schedule despite production problems, has now announced a six-month delay.

Deliveries of the fast-selling plane, originally scheduled to begin in May, have been pushed back to late November or December. There are 710 orders to date.

Boeing said the financial impact of the delay would not be material to earnings and that its earnings guidance for 2007 and 2008 remains unchanged.

"We are disappointed over the schedule changes that we are announcing today," Boeing's chief executive, Jim McNerney, said in a statement. "Notwithstanding the challenges that we are experiencing in bringing forward this game-changing product, we remain confident in the design of the 787 and in the fundamental innovation and technologies that underpin it."

The 787, a sleek, fuel-efficient plane, made its public debut this summer to much fanfare. It is competing against the long-haul, superjumbo A380 made by its European archrival, Airbus.